Fluid end construction for plunger pumps



Feb S, m69 w. J. MDM/xm ETAL 3,427,988

FLUID END CONSTRUCTION FOR PLUNGER PUMPS f'iled March 196'? my x THOMAS E. SCHMIEMAN WM )gf/dmv Arforney United States Patent Office i 3,427,988 Patented Feb. 18, 1969 2 Claims Int. Cl. F04b 19/22 ABSTRACT OF THE DISCLOSURE A fluid end construction in which the cylinder block has only two passages each of uniform diameter. One passage serves both as a cylinder bore and a suction passage. The other serves as a discharge passage. The construction eliminates points of stress concentration.

This invention relates to an improved liuid end construction for a plunger pump.

The fluid end of a conventional multiple-cylinder high-pressure plunger pump may be formed as an integral casting or fabricated from castings or forgings lbolted together. An integral casting is complicated and likely t be unsound because of the complex arrangement of passages needed. Corners at which passages interesect or change diameter are subject to unduly high stresses. Many times flaws do not appear until the part is machined or even tested hydrostatically. Most of these problems occur also in uid ends in which the parts are bolted together. Pumps of this type often handle corrosive liquids, and the complexity of the passages makes it difficult to protect their surfaces against corrosion.

An object of the present invention is to provide an improved fluid end construction which largely overcomes the foregoing problems, that is, which avoids complex passages in the cylinder block and diameter changes in t-hese passages.

A more specific object is to provide a fluid end construction in which the cylinder block has only two passages, each of uniform diameter throughout, namely a combined cylinder bore and suction passage and a discharge passage extending therefrom.

A further object is to provide a cylinder block which attains the foregoing advantages and in which the passage walls are prestressed in compression.

In the drawing:

FIGURE 1 is a longitudinal vertical sectional view of the fluid end of a pump constructed in accordance with our invention;

FIGURE 2 is a top plan view, partially broken away, of a modified cylinder block where we can use in the construction shown in FIGURE 1.

FIGURE 1 shows the fluid end of one cylinder of a multiple-cylinder plunger pump. The structure shown includes a cylinder block 10, a plunger 12, an `adapter 13 xed to one end of the cylinder block, a stuffing box 14 extending from the adapter, packing 15 within the stuffing box surrounding the plunger, and a gland 16 compressing the packing. The plunger is connected to a suitable reciprocating drive (not shown). In accordance with our invention, we form each cylinder block 10 of the pump as an individual piece, preferably a forging, although it can be cast. The block has horizontal and vertical passages 19 arrd 20. Passage 19 extends from one end of the block to the other and is of uniform diameter throughout. This passage reecives the plunger 12. Passage 20 extends upwardly from passage 19 through the top of the block and likewise is of uniform diameter throughout. The intersection between passages is smooth and rounded, as indicated at 21. Hence we have reduced the number of points where stresses concentrate, and the entire surface of both passages is accessible for finishing, as by shotpeening, or protecting against corrosion.

We connect the cylinder block 10 to suction and discharge manifolds 22 and 23. The block has stud bolts 24 which project from its end opposite the adapter 13 to attach the suction manifold 22, and stud bolts 25 which project upwardly from its top to attach the discharge manifold 23, A suction valve cage 26 and seat 27 afford communication between manifold 22 and the end of passage 19. A discharge valve cage 28 and seat 29 afford communication between the en-d of passage 20 and manifold 23. The suction and discharge valve cages 26 and 28 contain valves 30 and 31 respectively and springs 32 and 33 which urge the valves to their closed positions. We interpose packing rings 34 between the manifolds, valve cages and seats and the cylinder block. We connect the other cylinders of the pump to the same two manifolds in like manner. It is apparent also that the manifolds may be located elsewhere then we have illustrated, in which event they can be connected to the blocks through suitable pipes or elbows.

FIGURE 2 shows a cylinder block 10a of modified construction. The passages 19 and 20 are similar to those of the block already described; hence we have not repeated the description. Block 10a has two transverse horizontal bores 36 located on opposite sides of its vertical passage 20 above its horizontal passage 19. We insert compression bolts 37 in these Ibores and tighten nuts 38 on these bolts to precompress the block. Preferably we till the nuts with epoxy resin or equivalent after tightening to prevent their being loosened. Bolts 37 are located near the points of maximum stress in the passage Walls.

From the foregoing description it is seen that our invention affords a simple fluid end construction in which the cylinder block requires only two passages, both accessible and uniform in diameter. 'Ihe horizontal passage 19 serves both as a cylinder bore to accommodate the plunger 12 as it moves back and forth, and as a suction passage as the plunger is withdrawn. The vertical passage 20 serves as a discharge passage as the plunger advances.

While We have shown and described certain preferred embodiments of our invention, it is apparent that other modifications may arise. Therefore, we do not wish to be limited to the disclosure set forth but only by the scope of the appended claims.

We claim:

1. In a high-pressure plunger pump, an improved fluid end construction comprising:

a one-piece cylinder block having a first passage extending horizontally from one end of the block through the other end and a second passage extending vertically from said first passage through the top of the block;

both said passages being of uniform diameter throughout their lengths and the intersection therebetween being smooth and rounded;

a plunger movable lback and forth within said first passage;

a suction valve cage fixed to one end of said block outside the end of said first passage and communicating therewith;

a discharge valve cage xed to the top of said block outside the end of said second passage and communicating therewith;

respective suction and discharge valves mounted within said cages; and

respective suction and discharge manifolds connected to said cages;

said first passage serving as both a cylinder bore and a suction passage;

said second passage serving as a discharge passage.

2. A construction as defined in claim 1 in which said block has transverse hores on opposite sides of said second passage, and further comprising compression bolts in said bores precompressing said block.

References Cited UNITED STATES PATENTS 98,422 12/1869 Scott 103--153 2,357,434 9/1944 Taylor 103-153 3,373,695 3/1968 Yohpe 103-153 FOREIGN PATENTS 736,330 6/ 1943 Germany. 370,580 4/ 1932 Great Britain. 549,053 10/ 1956 Italy.

DONLEY I. STOCKING, Primary Examiner. 

